Polishing motor problem...not enough umph to spin!

Hi everyone,
My polishing motor is playing up- just doesn’t have enough power to start up.
If I switch it on the fuse blows but if I manually start the spindel spinning and then switch on it works fine…
Any ideas of whats up and how to fix?

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Hello Annika, have you tried contacting the manufacturer, they should be able to guide you. Regards, Richard Lucas

Generally speaking, a bench jewellers polishing setup is fractional HP, ie under 1hp. That said, these are induction motors with 2 sets of windings. a start winding and run winding. ~With a centrifugal switch to change over from one to the other. Also to kick start the motor theres a capacitor in line with the Start winding. so it could be,

  1. The capacitor has failed, they do,
    2 .centifugal sw is sticking on or wont unstick…
    from your description it sounds like the former.
    you need to take it to a motor repair shop for checking.
    Should be able to do that while you wait.
    then fit a new cap as well to get you back up and running.

many thanks for the advice…glad it sounds like a quick fix. but obviously unfortunate not something I can try fixing myself.
thanks Again

good thinking Lucas.
Hope they are still around as have had machine for 15 years (so suppose I can’t complain)

When you say the fuse blows are you talking about the reset button on the motor or a circuit breaker? I’m just wondering if maybe your motor got hot and the reset button on the motor itself popped? If so resetting it might fix your problem. If not it might be a wiring issue with your cord, the outlet or, less likely, in the motor itself. Usually polishing motors just go forever. So I would try it in another outlet as well. Just to isolate the problem with the motor. Just some thoughts. Mark

I think Ted nailed it. It is most likely a shorted starting capacitor. If you have a multimeter you could check it for a short by setting it to high ohms and touch the leads to the terminals. If it starts out at a low reading and climbs to a high one the capacitor is probably good. If it stays low it is shorted. But even without testing if it runs when you rotate it but blows a fuse if you don’t do that the only thing different is the starting capacitor being in or out of the circuit. You can actually order one.

Just find it on the motor. (it will be tubular shaped rounded or oval)

See what the value is that is printed on it.

Google “induction motor capacitors”

You should then get a bunch of sites to get a replacement and order one that matches what you have.

Should not cost more than a few dollars.

When you get it just disconnect the old one and put on the new one making sure you replace the wires to the same terminals that you took the old ones off of.


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Fantastic Mia
I do have a multimeter so will check that today and try this route.
Excellent help much appreciated